Slim Case?

[SpellowHouse]

I have an ATX motherboard with a 9700K. It's an old gaming PC that has been degraded to a media PC. It doesn't have a GPU card in there, so could happily fit in a slim case. Problem is, I can't find one. Every time I search for one, I get shown MATX or Micro cases. Are there any slim cases for ATX motherboards these days?

 

[SpellowHouse]

I can't find either for sale now. Seems I missed them.

I'm coming to the conclusion that the only thing to do is to replace the motherboard with a MATX, then the case. Something I don't want to do at the moment.